Strongly agree with your point that “what an organization doesn’t report says more about their bias than what they do report.”
Mainstream western news media can’t be faulted for reporting large pro Guaido demonstrations, and they have occasionally also mentioned large pro Maduro marches and rallies. (E.g. In this recent report by the BBC.) Where the bias comes in, is that they’ve given the pro Maduro crowds vastly less coverage.
Looking at the Pompeo tweet which you quoted at the start of your article, there’s an important point Pompeo didn’t mention…
The withdrawal of the US embassy is something Maduro has been publicly demanding for over a month now, while Guaido has publicly opposed that demand.
Pompeo (obviously) doesn’t want to admit that the withdrawal of the US staff is a victory for Maduro. The fact remains that Maduro, not Guaido, got the outcome he wanted.